Research and Teaching Interests

Dr. Walker's research is in the field of radiation chemistry­, the study of the physical, chemical, and biological effects of high-energy (ionizing) radiations. As our lives are entwined with nuclear radiations ­for good and not so good reasons ­it is necessary to try to understand the processes involved when ionizing radiations interact with matter, so that it will be possible to predict, control, and alter their effects.

In aqueous media (including most of the biosphere), high energy radiations initially produce H-atoms, hydrated electrons and OH radicals from the water; and these then react with organic matter present to produce overall chemical (and biological) changes. Research here is directed to an understanding of the primary chemical reactivity of H-atoms by studying its pseudo-isotope muonium (one-ninth the mass of H) and making comparisons with positronium. The muonium research is conducted at the TRIUMF cyclotron on campus and focusses on rare kinetic isotope effects. Radiation chemistry studies of solvated electrons utilize a Co-60 gamma source, and the positronium work uses fast positron annihilation lifetime equipment in the Chemistry Department.